1. Colonoscopy
- How it's done
- Visual exam of the whole colon with a scope, under sedation
- How often
- Every 10 years
- Good to know
- The most thorough test; polyps are removed during the same visit. Needs bowel prep and a driver home.
Focus On…
Colorectal Cancer Screening: Your Options
Adults at average risk should start colorectal cancer screening at age 45. Screening finds cancer early, when it is most treatable, and some tests find and remove polyps before they ever turn into cancer. The best test is the one you actually complete, so there are several good options.
Who should be screened, and when
| Age | Recommendation (average risk, no symptoms) |
|---|---|
| 45–75 | Screen regularly with any recommended test |
| 76–85 | Decide with your doctor, based on your health, life expectancy, and past screening; those never screened benefit most |
| Over 85 | Routine screening is no longer recommended |
Start earlier or screen more often if you are at higher risk — for example, if you have a parent, sibling, or child with colorectal cancer or advanced polyps, a personal history of polyps or colorectal cancer, Crohn's disease or ulcerative colitis, or an inherited syndrome such as Lynch syndrome or FAP. People with a close family history often begin with colonoscopy at age 40, or 10 years before the relative's age at diagnosis, whichever comes first.
Symptoms are not screening
Rectal bleeding, blood in the stool, a lasting change in bowel habits, belly pain, or unexplained weight loss need prompt evaluation by a doctor at any age.
Your screening options
Tests are listed from most to least preferred, based on how well each finds cancer and precancerous polyps.
2. FIT (fecal immunochemical test)
- How it's done
- At-home stool sample, mailed to a lab
- How often
- Every year
- Good to know
- First-choice at-home test. No prep, no diet changes, low cost. Must be repeated yearly.
3. Stool DNA test (Cologuard / Cologuard Plus)
- How it's done
- At-home stool sample, checks for DNA changes and blood
- How often
- Every 3 years
- Good to know
- No prep. Finds more cancers than FIT on a single test, but has more false positives.
4. Stool RNA test (ColoSense)
- How it's done
- At-home stool sample, checks for RNA markers and blood
- How often
- Every 3 years
- Good to know
- Newer at-home option added to ACS guidelines in 2026.
5. CT colonography (virtual colonoscopy)
- How it's done
- CT scan of the colon
- How often
- Every 5 years
- Good to know
- No sedation, but needs bowel prep. Polyps found still need a colonoscopy.
6. Flexible sigmoidoscopy
- How it's done
- Scope exam of the lower third of the colon
- How often
- Every 5 years (or every 10 years with yearly FIT)
- Good to know
- Less prep than colonoscopy, but misses the upper colon; less widely available.
7. High-sensitivity gFOBT (guaiac test)
- How it's done
- At-home stool samples
- How often
- Every year
- Good to know
- Less accurate than FIT; may require diet and medication changes before testing.
8. Blood test (Shield)
- How it's done
- Simple blood draw
- How often
- Every 3 years (per manufacturer)
- Good to know
- Only for people who decline or won't complete the tests above. Misses more early cancers and most precancerous polyps.
Choosing a test, and what comes next
- Talk with your clinician about your risk, preferences, and insurance coverage. Most plans cover recommended screening starting at 45.
- An abnormal at-home stool or blood test is not a diagnosis, but it must be followed by a colonoscopy, ideally within 6 months. Screening isn't complete until that colonoscopy is done.
- Stay on schedule. At-home tests only work if repeated at the recommended interval.
This page is for general education and does not replace advice from your clinician. Based on the U.S. Preventive Services Task Force and American Cancer Society guidelines (updated May 2026). Sources: American Cancer Society 2026 guideline update · USPSTF colorectal cancer screening recommendation.